lb/hr to kg/s Calculator

Common Mistakes Quick tips

Entering values in both fields. Fill exactly one: either lb/hr (or related lb-based unit) or kg/s (or related SI unit).
Mixing time bases. Be sure the dropdown matches your entry (per hour vs per minute vs per second).
Confusing ton types. This tool’s ton/hr option is US short ton (2000 lb), not a metric tonne (1000 kg).
Using rounded factors. This tool uses the exact relation 1 lb = 0.45359237 kg and 1 hr = 3600 s, so results may differ slightly from calculators using 0.454 or 0.000126.

When to Use This Calculator

Quickly convert mass flow between US customary (lb-based) and SI (kg-based) units.
Standardize units across process sheets, instrumentation readouts, or engineering calculations.
Not a substitute for engineering judgment; validate unusual results and unit selections.

Input Definitions

lb/hr — pounds of mass per hour (US customary mass flow).
kg/s — kilograms of mass per second (SI mass flow).
Conversion — kg/s = lb/hr × 0.45359237 ÷ 3600; lb/hr = kg/s × 3600 ÷ 0.45359237.

Convert mass flow rates between lb/hr, lb/min, lb/s, US ton/hr and kg/s, kg/min, kg/hr, or g/s by entering a value in either unit.

lb/hr to kg/s Formula

The following formula is used to convert lb/hr to kg/s.

kg/s = (0.45359237/3600) * lb/hr

Where kg/s is the kilograms per second
lb/hr is the pounds per hour

To calculate kg/s from lb/hr multiply the lb/hr by 0.45359237 and divide by 3600.

Pounds per hour to Kilograms per second Conversion Table (Mass flow)
Pounds per hour (lb/hr)	Kilograms per second (kg/s)
1	0.000126
5	0.000630
10	0.001260
20	0.002520
25	0.003150
50	0.006300
75	0.009450
100	0.012600
150	0.018900
200	0.025200
250	0.031499
300	0.037799
400	0.050399
500	0.062999
750	0.094498
1,000	0.125998
1,500	0.188997
2,000	0.251996
5,000	0.629989
10,000	1.259979
US customary: 1 lb = 0.45359237 kg; 1 hr = 3600 s. Therefore, 1 lb/hr ≈ 0.0001259979 kg/s.

How do you convert lb/hr to kg/s? Multiply the flow in lb/hr by 0.45359237 to convert pounds to kilograms, then divide by 3600 to convert hours to seconds.

How do you convert kg/s to lb/hr? Multiply the flow in kg/s by 3600, then divide by 0.45359237; equivalently lb/hr = kg/s × 3600 ÷ 0.45359237.

Example Problem

How to calculate kg/s from lb/hr?

First, determine the total number of pounds per hour.

For this example, the total lb/hr is found to be 3600.

Next, use the formula for the conversion above to determine the amount of kg/s.

kg/s = 0.45359237/3600 * lb/hr

kg/s = 0.45359237/3600 * 3600

kg/s = 0.45359237

lb/hr to kg/s Formula

Example Problem